Fixing the timing on a Kenmore sewing machine is not as difficult as you might think. Every once in a while, the sewing machine's timing needs adjustment simply because the machine was used. If you notice stitches are off a little bit or that the machine doesn't stitch properly and you cleaned it, re-threaded it and adjusted its tension, then timing may be the problem.
Remove the plate covering the bobbin. Use the screwdriver that came with the Kenmore sewing machine to make the task a little easier.
Check where the point of the needle and the bobbin casing meet. Turn the hand wheel slowly by hand, and notice whether the bobbin casing goes by before the needle comes down or vice versa.
Move elements out of the way. Set the stitch length at four, and raise the needle to its highest position so you can work underneath it. Either raise the presser foot or remove it so you have a good view of the feed dogs.
Loosen the only screw in this spot of a Kenmore sewing machine that requires a regular flat-head screwdriver. It's usually the upper screw.
Turn the eccentric pin slightly with an Allen wrench. The eccentric pin is just below the screw you just loosened with a flat-head screwdriver. Turn the eccentric pin slightly one way to adjust the height of the feed dogs. If the feed dogs go down, adjust the eccentric pin in the opposite direction.
Test the height of the feed dogs. When you turn the hand wheel, the feed dogs should come up 0.04 inches, or 1.016mm, on the Kenmore sewing machine, which is enough for the feed dogs to move fabric along while you sew. Turn the eccentric pin a little bit more if the feed dogs are still not at the right height to fix the timing.
Return your sewing machine to as it was before. Tighten all the screws, and replace the plate covering the bobbin.
Test your sewing machine. Set the stitch length to "2." Insert a piece of scrap fabric, and turn the hand wheel slowly to ensure that the needle won't hit the bobbin casing. Test the timing further by stepping on the pedal and allowing the sewing machine to work faster and the feed dogs to move the fabric through, forming the stitches properly.